Recently I transfered my Windows 10 to SSD drive and have other 2 HDD in my pc and moved some system folders to drive D cause my SSD is only 120Gb. Two days ago I updated the driver to the beta version but after restart my computer did not boot. Checking the system I realised that every drive letter (volume) was changed. After assigning the correct letters rebuilding BCD and fixing boot and mbr the system started again. Yesterday I decided to test the main version of the drive and after restart the same thing happened again. Now I corrected the volume letters and everything is working again, but anyone could tell what happened? The drive letters should not be affected by the driver installation. Could be because the presence of the SSD?

Yes, most likely Windows is trying to "find" those Windows system files and can't.

If you run SFC /scannow in a elevated Command Prompt, It will likely reinstall those missing Windows system files on the main SSD Drive. If is can't then you need to download a small program called SFCfix which basically runs DISM to download and reinstall all missing Windows files.

120gb should be large enough to install the entire WIndows OS on it. What you need to do is whenever you install a program or software, have it installed on a regular Hard Drive rather than on the SSD.

I would do a clean re-installation of Windows and then re-install all your programs and software on Drive D if there isn't enough room on the SSD with all your programs installed.

No system file is missing and after using diskpart to change the letters everything go back to normal. I will do a clean installation in the future that will fit Windows more properly in the SSD. I don't know how a simple driver upgrade can change those letters and mess up a normaly operating system.

What is the Make & Model of your motherboard? Sometimes BIOS needs to be updated to make the newer SSD more compatible with the motherboard and WIndows. Also see if there are any updated drivers from your motherboard's manufacturer support site concerning drivers for SSDs or hard drives.

I also agree with your view. A GPU driver shouldn't change the Hard drives letters. I believe you are the first Users to mention that odd problem here at AMD Forum. So most likely it is something to do with your Windows OS installation.

Your motherboard is at least 5 years old. Is your motherboard version 1.0? if so, here is the ECS Support driver and BIOS download link for your motherboard: ECS > H61H2-M17 .

These are the SSD that your motherboard supports: ECS > H61H2-M17 . It doesn't show any Western Digital SSD on the list. You may want to contact ECS Support and find out if the problems you are having could be incompatibilities between the Western Digital SSD and motherboard. Need to click on the tab that says "Storage" and there it will show you all the Hard drives and SSD your motherboard supports. It does have Western Digital but Hard drives and not SSD.